An efficient ultrasound promoted catalyst-free protocol for the synthesis

of chromeno[4,3-b]quinolin-6-ones

J VENKATA PRASAD, J SATYANARAYANA REDDY, N RAVI KUMAR,

K ANAND SOLOMON and G GOPIKRISHNA^*

Sankar Foundation Research Institute, Visakhapatnam 530047, India

e-mail: gkrishnagps@gmail.com

MS received 31 December 2010; revised 24 May 2011; accepted 30 May 2011

Abstract. A convenient, catalyst-free protocol for the quantitative synthesis of fused chromeno[4,3-

b]quinolin-6-ones has been developed by simple one-pot reaction of substituted anilines with 4-chloro-3-

formylcoumarin using ultrasound irradiation. The protocol offers the advantages of mild reaction conditions,

short reaction times and high yields.

Graphical Abstract. Tetracyclic chromeno-quinolines are precipitated as pure products from the

reaction of 4-chloro-3-formyl-coumarin and aromatic anilines in ethanol under

ultrasound irradiation.

Keywords. Ultrasound; 4-chloro-3-formylcoumarin; anilines; chromeno-quinoline.